Chris Hornbeck wrote:
On 14 Apr 2005 19:40:17 -0700, "Mark" wrote:

the DIM 30 test signal as you described it passes through a 30 kHz low
pass filter. Therefore almost any square wave signal generator will
have a suffienctly fast rise and fall time i.e. slew rate for this test
since it will be limited by the 30 kHz LPF anyway.

It's certainly scary that David's tests found so many mic preamps
that performed so poorly. It's just these (un)bandwidth-limited
locations that are at greatest risk of out-of-band overloads.

I'm not surprised a bit. An excellent rough test is just to run a
1 KHz square wave through a given piece of equipment and eyeball it on
a scope. The square wave calibrator on a Tek scope works well enough
for the job.

You would not _believe_ how nasty things look going through some of the
inexpensive fake tube preamps. Not to mention some of the cheap
microphone transformers out there.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."